/**
 * 
 */
package cn.com.compass.util;

import java.awt.geom.Point2D;
import java.util.List;

/**
 * @author hexiaomei
 *
 */
public class EarthMapUtil {
	/**
	 * 高德转百度
	 * @param gd_lon
	 * @param gd_lat
	 * @return
	 */
	public static double[] gaoDeToBaidu(double gd_lon, double gd_lat) {
	    double[] bd_lat_lon = new double[2];
	    double PI = Math.PI * 3000.0 / 180.0;
	    double x = gd_lon, y = gd_lat;
	    double z = Math.sqrt(x * x + y * y) + 0.00002 * Math.sin(y * PI);
	    double theta = Math.atan2(y, x) + 0.000003 * Math.cos(x * PI);
	    bd_lat_lon[0] = z * Math.cos(theta) + 0.0065;
	    bd_lat_lon[1] = z * Math.sin(theta) + 0.006;
	    return bd_lat_lon;
	}
	/**
	 * 百度转高德
	 * @param bd_lat
	 * @param bd_lon
	 * @return
	 */
	public static double[] baiduToGaoDe(double bd_lat, double bd_lon) {
	    double[] gd_lat_lon = new double[2];
	    double PI = Math.PI * 3000.0 / 180.0;
	    double x = bd_lon - 0.0065, y = bd_lat - 0.006;
	    double z = Math.sqrt(x * x + y * y) - 0.00002 * Math.sin(y * PI);
	    double theta = Math.atan2(y, x) - 0.000003 * Math.cos(x * PI);
	    gd_lat_lon[0] = z * Math.cos(theta);
	    gd_lat_lon[1] = z * Math.sin(theta);
	    return gd_lat_lon;
	 }

    //地区半径 千米
    private static double EARTH_RADIUS=6378.137;

    /**
     * 计算弧度
     * @param d
     * @return
     */
    public static double rad(double d){
        return d * Math.PI / 180.0;
    }

    /**
     *  返回当前坐标与目标坐标的距离(米)
     * @param targetLat
     * @param targetLng
     * @param localLat
     * @param localLng
     * @return
     */
    public static double subDistance(double targetLat,double targetLng,double localLat,double localLng){
        //计算两点间的差距
        double lat = rad(targetLat)-rad(localLat);
        double lng = rad(targetLng)-rad(localLng);
        double distance = 2 * Math.asin(Math.sqrt(Math.pow(Math.sin(lat / 2), 2) +
                Math.cos(rad(targetLat)) * Math.cos(rad(localLat)) * Math.pow(Math.sin(lng / 2), 2)));
        distance = distance * EARTH_RADIUS;
        distance = Math.round(distance*10000d)/10000d;
        distance = distance*1000;//km->m
        return distance;
    }
    
    /** 
	 * 判断点是否在多边形内 
	 * @param point 检测点 
	 * @param pts   多边形的顶点 
	 * @return      点在多边形内返回true,否则返回false
	 */  
	public static boolean IsPtInPoly(Point2D.Double point, List<Point2D.Double> pts){  
	      
	    int N = pts.size();  
	    boolean boundOrVertex = true; //如果点位于多边形的顶点或边上，也算做点在多边形内，直接返回true  
	    int intersectCount = 0;//cross points count of x   
	    double precision = 2e-10; //浮点类型计算时候与0比较时候的容差  
	    Point2D.Double p1, p2;//neighbour bound vertices  
	    Point2D.Double p = point; //当前点  
	      
	    p1 = pts.get(0);//left vertex          
	    for(int i = 1; i <= N; ++i){//check all rays              
	        if(p.equals(p1)){  
	            return boundOrVertex;//p is an vertex  
	        }  
	        p2 = pts.get(i % N);//right vertex              
	        if(p.x < Math.min(p1.x, p2.x) || p.x > Math.max(p1.x, p2.x)){//ray is outside of our interests                  
	            p1 = p2;   
	            continue;//next ray left point  
	        }  
	        if(p.x > Math.min(p1.x, p2.x) && p.x < Math.max(p1.x, p2.x)){//横坐标 内  ray is crossing over by the algorithm (common part of)  
	            if(p.y <= Math.max(p1.y, p2.y)){//y下  x is before of ray                      
	                if(p1.x == p2.x && p.y >= Math.min(p1.y, p2.y)){//overlies on a horizontal ray  垂线
	                    return boundOrVertex;  
	                }  
	                if(p1.y == p2.y){//水平线 ray is vertical                          
	                    if(p1.y == p.y){//水平线内 overlies on a vertical ray  
	                        return boundOrVertex;  
	                    }else{//before ray  
	                        ++intersectCount;  //交点在上方
	                    }   
	                }else{//cross point on the left side                          
	                    double xinters = (p.x - p1.x) * (p2.y - p1.y) / (p2.x - p1.x) + p1.y;//两点式化简，交点y坐标 cross point of y                          
	                    if(Math.abs(p.y - xinters) < precision){//== 0  在线上  overlies on a ray  
	                        return boundOrVertex;  
	                    }  
	                      
	                    if(p.y < xinters){//before ray  
	                        ++intersectCount;  //交点在上方
	                    }   
	                }  
	            }  
	        }else{//special case when ray is crossing through the vertex                  
	            if(p.x == p2.x && p.y <= p2.y){//p crossing over p2                      
	                Point2D.Double p3 = pts.get((i+1) % N); //next vertex                      
	                if(p.x >= Math.min(p1.x, p3.x) && p.x <= Math.max(p1.x, p3.x)){//p.x lies between p1.x & p3.x  
	                    ++intersectCount;  
	                }else{  
	                    intersectCount += 2;  
	                }  
	            }  
	        }              
	        p1 = p2;//next ray left point  
	    }  
	    if(intersectCount % 2 == 0){//偶数在多边形外  
	        return false;  
	    } else { //奇数在多边形内  
	        return true;  
	    }  
	} 
}
